Resuscitation of accident victims, or persons suffering from a sudden illness, conventionally involves mouth-to-mouth contact with the victim. This is both tiring, and physically distasteful and, in some cases, almost impossible. For example, where the victim is located in a confined space, it may be impossible for an assistant to place his head in the necessary position.
In order to overcome some of these problems, tubular devices have been manufactured, which avoid the actual physical contact with the mouth of the victim. However, it is still necessary for the assistant to use his own lungs.
Another disadvantage of mouth-to-mouth resuscitation is the fact that the victim is not receiving clean air, but is receiving air from the lungs of the assistant. Ambient air normally contains about 22% free oxygen whereas exhaled air contains about 16% free oxygen. In addition, there is the inherent danger of the communication of disease.
Numerous devices have been proposed and are on the market, involving some form of air bag, and face mask or breathing tube or other breathing device to overcome these problems. The air bag is designed to be squeezed, at appropriate intervals, while the mask or other device is held over the face of the victim. The construction of the air bag should preferably be such that it can be squeezed with one hand.
In many cases the construction of these manual devices is relatively complex, involving the use of, for example, interior springs within the air bag, and complex valves, such that the cost of manufacture is relatively high. As a result, such manual devices have not achieved wide distribution. In many cases, their use is effectively restricted, by virtue of their high price, to professional health care services, such as ambulances, first aid points, and hospital emergency rooms.
This is unfortunate, since of course such emergency equipment should preferably achieve mass distribution, so that it is immediately available. For example, it would be desirable to include such emergency devices in all first aid kits carried on boats, trucks, automobiles, work sites, and recreation centres and in the home.
In addition, such emergency devices as are presently on the market, have incorporated relatively complex valve systems, so as to control the flow of air into and out of the breathing mask. The function of such emergency devices is, of course, to ensure that fresh air is supplied to the victim, and that air exhaled by the victim is vented to atmosphere and is not returned to the air bag. In order to achieve this result it is necessary to have an air flow valve which permits air to flow from the bag into the mask, but which prevents return flow, and in addition, a further valve which permits air to flow from the mask to atmosphere, but which does not permit air to flow from the bag to atmosphere, since otherwise there would be no air pressure sufficient to inflate the lungs of the victim.
The design and construction of valving systems in such prior art devices has been relatively complex, which has been one of the factors in the relatively high cost involved. In addition to this, however, if the victim should discharge water or vomit into the face mask, there is a strong possibility that one of the valves will fail.
For these reasons it is desirable to both simplify the construction of the valve, and also avoid the use of small components, springs and the like, which may be a source of trouble.
A further factor limiting the use of prior art breathing devices has been the need for sterilization. In most cases this has been achieved simply by having a replaceable face mask. However, since the victim will in fact be breathing in and out through the tubing and valve systems, these too should preferably be either sterilized or replaceable. In practice, however, this requirement has not been met.
Sterilization of components is relatively time consuming, and unless trained personnel are available, it will not be carried out satisfactorily. In addition, it requires components which are made of materials capable of withstanding high temperatures, and which must be easily dismantled and reassembled. This greatly increases the expense and, in addition, introduces the further possibility that the parts may be reassembled in the wrong way, so that the device does not function at all.
For all of these reasons, it is considered highly desirable to produce a low-cost, simple, economical emergency breathing device of the type described, which is intended for a one-time use only, and is then simply discarded and replaced with a new one. It is also desirable to greatly simplify the function of the valve, and keep the components relatively large, and eliminate the use of springs, so that if during use, some obstruction should interfere with the operation of the valve, it can readily be removed.